I they are flickering when off odds are very good it is in fact a Timer Issue,, they are not all the way off.. However that said........
Florcesent lamps can be lit even with NO power to them or even wires to them.
Radar will make them light.. A Tesla coil.. High power radio transmitters... Microwave Radiation.. You may have a serious problem there.
Remove the lamp from the socket and let it sit upside down.. IF it still flickers you have a serious issue.. MOVE,, FAST or get a radiological survey done.